Advances in Smalltalk / Lecture Notes in Computer Science Bd.4406 (PDF)

Application-Specific Models and Pointcuts Using a Logic Meta Language (p. 8)1 Introduction

Aspect-oriented Software Development (AOSD) is a recent, yet established development paradigm that enhances existing development paradigms with advanced encapsulation and modularisation capabilities [1,2]. In particular, aspect-oriented programming languages provide a new kind of abstraction, called aspect, that allows a developer to modularise the implementation of crosscutting concerns such as synchronisation, transaction management, exception handling, etc.

Such concerns are traditionally spread across variousmodules in the implementation, causing tangled and scattered code [3]. The improved modularity and separation of concerns [4], that can be achieved using aspects, intends not only to aid initial development, but also to allow developers to better manage software complexity, evolution and reuse.

One of the most essential characteristics of an aspect-oriented programming language is that aspects are not explicitly invoked but instead, are implicitly invoked [5]. This has also been referred to as the ‘obliviousness’ property of aspect orientation [6]. It means that the base program (i.e., the program without the aspects) does not explicitly invoke the aspects because the aspects themselves specify when and where they need to be invoked by means of a pointcut de.nition.

A pointcut essentially specifies a set of join points, which are specific points in the base program where the aspect will be invoked implicitly. Such a pointcut de.nition typically relies on structural and behavioural properties of the base program to express the intended join points. For example, if an aspect must be triggered at the instantiation of each new object of a particular class, its pointcut must capture those join points whose properties correspond with the execution of the constructor method.

As a result, each time the